l = []
l.append(5)
l.append(7)
l.append(2)
l.append(6)
l.append(9)
l.append(1)
print l
def reverse(l):
	for n in range(0, len(l)-1, 2):
		tmp = l[n]
		l[n] = l[n+1]
		l[n+1] = tmp
	return l
print reverse(l)
